Payments processor Worldpay Group has priced its initial offer at 240p per ordinary share - almost exactly in the middle of expectations - meaning the company will have a market cap of £4.8bn when it goes public.
This makes it the biggest float this year, easily besting Auto Trader, which went public in March with a valuation of £2.3bn.
Private equity owners Bain Capital and Advent International had looking at an offer of between 225p to 260p, though this was narrowed on Friday to between 235p to 250p.
The offer is expected to raise total gross proceeds of approximately £2.16bn, assuming the over-allotment option is not exercised, or £2.48bn assuming that the over-allotment is exercised in full. Worldpay will receive around £947.8m of gross proceeds from the offer.
Worldpay's private equity owners will hold around 49 percent of the company's shares.
Worldpay will be seeking to join the FTSE UK at the quarterly review in December 2015.
“Today’s announcement is a significant milestone for Worldpay," said chief executive Philip Jansen. "We welcome our new investors and thank them for the strong interest they have shown in the offer. We look forward to developing as a public company and all the opportunities this will bring."
Worldpay was sold by RBS five years ago for around £2bn.